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C. R. Geoscience 346 (2014) 179–189
Contents lists available at ScienceDirect
Comptes Rendus Geoscience
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Petrology, Geochemistry
First African diamonds discovered in Algeria by the ancient
Arabo-Berbers: History and insight into the source rocks
Gaston Godard a,*, Moulley Charaf Chabou b, Zouhir Adjerid c,
Abderrahmane Bendaoud d
a
Institut de physique du Globe, Sorbonne Paris Cité, Université Paris-Diderot, UMR 7154 CNRS, 1, rue Jussieu, 75238 Paris cedex 05, France
Université Ferhat-Abbas, Sétif 1, Institut d’architecture et des sciences de la Terre, département des sciences de la Terre, campus El-Bez,
19000 Sétif, Algeria
c
École normale supérieure, département des sciences naturelles, BP 92, Vieux Kouba, 16050 Alger, Algeria
d
Université des sciences et des techniques Houari-Boumédiène, BP 32, Dar el Beida, 16111 Alger, Algeria
b
A R T I C L E I N F O
A B S T R A C T
Article history:
Received 26 February 2014
Accepted after revision 21 March 2014
Available online 10 July 2014
It is generally believed that the first diamonds ever found in Africa were discovered in
South Africa in 1867. Actually, three diamonds had already been found in 1833 near
Constantine (Algeria). One of these, still preserved, shows radiohalos that suggest an old
age. It could be a Sahara diamond reworked in more recent sediments, possibly the OligoMiocene Numidian Flysch; however, this occurrence remains uncertain. The ancient Arabs
or Berbers also knew of diamonds in the Reggane region (Algerian Sahara), at Bilād al-mās
: ‘‘country of the diamond’’). Since 1975, some 1500 diamonds have been
(
collected from the alluvial deposits of this area. A manuscript written in Arabic in 1851
mentions diamonds in this region and describes their source rock, looked for in vain by
modern geologists. The description is unclear, but might refer to Devonian oolitic
ironstones. Modern investigations would rather suggest a kimberlitic primary source with
intermediate Early Cretaceous palaeoplacers.
ß 2014 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Keywords:
Diamond
Emerald of the Garamantes
Lamproite
Numidian Flysch
Radiohalos
Constantine
Sahara
Algeria
1. Introduction
Until the 18th century, India was the only known source
of diamond. However, a few antique chronicles recounted
that diamond also existed in northern Africa. Pliny, in
particular, says in his Naturalis Historia (37.55) that the
diamond existed in Ethiopia – that is, to the South of Egypt.
It has also been reported that the Carthaginians exchanged
precious stones, among which were diamonds, with the
interior of Africa (e.g., Agricola, 1546; Heeren, 1799).
More recently, in 1834, the ‘‘Muséum national d’histoire naturelle’’, Paris, purchased a diamond reportedly
* Corresponding author.
E-mail address: [email protected] (G. Godard).
found in the Ghoumel River, near Constantine (Algeria). In
addition, the papers of Du Couret’s Saharan mission (1849–
1852) include an Arabic manuscript that describes
diamonds in the Reggane region, which were rediscovered
by modern exploration as late as 1975. Although it is
frequently asserted that the first diamonds ever found on
the African continent were discovered in South Africa in
1867, it seems that the Arabs and/or Berbers knew of
diamonds in Algeria well before the colonial era.
A historical investigation of the Algerian diamonds,
interesting in itself, also carries some geological interest. It
may clarify the still enigmatic origin of the diamonds from
Constantine and can provide indications in the quest for
the source rock of the Sahara diamonds, for which modern
geologists have searched for decades. Here, we relate the
history of the diamond discoveries near Constantine and
http://dx.doi.org/10.1016/j.crte.2014.03.007
1631-0713/ß 2014 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.
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180
G. Godard et al. / C. R. Geoscience 346 (2014) 179–189
then in the Algerian Sahara, and recall forgotten historical
information that may be useful for the knowledge and
exploration of these deposits.
2. The Constantine diamonds
2.1. History of the finds
Saint Augustine, born in 354 AD in Thagaste (now Souk
Ahras) at 125 km from Constantine (Fig. 1a) and bishop of
Hippo (now Annaba, 120 km northeast of Constantine),
evokes diamonds in his De Civitate Dei (21.4), but specifies
neither their origin nor where he observed them. The first
mention of a diamond from Constantine dates back to the
18th century; Magalotti (1721, pp. 228–230; 1741,
pp. 206–215) reports that a merchant from Constantine
brought to Livorno in Tuscany a cut and engraved diamond
of the ‘‘half size of a hazelnut’’.
Later, in 1833, Paolo Francesco Peloso [1793–1856],
consul of Piedmont-Sardinia at Algiers, sold to the French
three diamonds reportedly found by a ‘‘native’’ in the
auriferous gravels of the Ghoumel River, near Constantine.
Two of these diamonds were shown in Algiers in November
1833 at an exhibition of the natural resources of Algeria
Fig. 1. (Colour online.) Diamond in Algeria: a: diamond finds; b: map of the Reggane region (dashed line: ancient caravan route between Akabli and
Ouallen).
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G. Godard et al. / C. R. Geoscience 346 (2014) 179–189
181
Table 1
Location of the Constantine diamonds, according to various authors.
Authors
Muséum National d’Histoire Naturelle (MNHN)
École des mines
De Drée’s collection
Anonymous (1835a,b,c)
1 diamond
1 diamond
1 diamond
Élie de Beaumont (1838, p. 152)
2 diamonds
Héricart de Thury (1840)
1 diamond (1.25 carat = 250 mg)
1 diamond (3 carats)
1 diamond (1 carat)
Lacroix (1893–1913, vol. 2, p. 354)
1 diamond (octahedron of 91 mg)
This study
1 diamond (rounded octahedron of 91 mg)
Not found
Sold to MNHN in 1844; not found
(Guyon, 1834). In 1834, a French officer named LouisCharles-Albert Sayde de Bellecôte [1807–1872] negotiated
the sale of these diamonds to three mineralogical
collections in Paris, namely ‘‘École des mines’’, ‘‘Muséum
national d’histoire naturelle’’ [MNHN] and Étienne de
Drée’s private collection (Anonymous, 1835a). The discovery was presented at the ‘‘Société géologique de
France’’ (Dufrénoy, 1834) and the ‘‘Académie des sciences’’
(Élie de Beaumont, 1838; Héricart de Thury, 1840; Table 1).
Several American and European periodicals of the time
echoed the find (e.g., Anonymous, 1835a,b,c; d’Avezac de
Castera-Macaya, 1835–1836; Dureau de La Malle, 1837;
see Boutan, 1886), which they presented as the first
discovery of diamond ever made in Africa – the South
African diamonds were discovered later, in 1867.
The geologists who worked in Algeria during the 19th
century were embarrassed about this find, which they
considered as a hoax and thus soon forgot. The geology of
the Constantine province, which consists mostly of
Mesozoic marine sediments hardly favourable to the
presence of diamond, as well as the lack of new discoveries,
discredited the find. It must also be recalled that, in the
middle of the 19th century, diamond was known to occur
only in India, Borneo and Brazil. Émilien Renou (1848)
thought that the so-called Algerian diamonds may have
come from the ‘‘pays de Bornou’’ (i.e., Chad region). In
1849, Henri Fournel, a leader of the Saint-Simonian
movement, proposed a strange origin for these diamonds;
in his Richesse minérale de l’Algérie, he imagines that they
could have belonged to one of the adulterous women who,
according to an ancient tale, were thrown into the
Ghoumel gorge at Constantine during Roman times
(Fournel, 1849–1854). As for the geologists who studied
the Constantine region after Fournel, they simply ignored
the diamonds (e.g., Coquand, 1854; Joleaud, 1912; Ville,
1869). The mineral catalogue of Algeria published in 1873
by Alexandre Papier does not mention them. It looks like an
oversight; however, Papier certainly knew Bellecôte, who
in 1834 had negotiated the sale of the diamonds in Paris,
since they both lived in Bône (now Annaba) and were both
members of the Académie d’Hippone. It seems that Papier
(1873) deliberately ignored the Constantine diamonds.
Fournel’s hypothesis is indeed absurd, as the Romans
were certainly not stupid enough to throw jewels away
with their victims, but a hoax remains nevertheless
possible. When the French entered the Kasbah of Algiers
on 5 July 1830, they seized the treasury of the Dey of
Algiers, Hussein Pasha. Soon afterwards, because of the
French revolution of July 1830 and the subsequent
abdication of King Charles X, the chiefs of the expedition
were forced to leave Algiers and fled into exile. When the
new French regime sent its own administrators to Algiers,
most of the gold, silver and precious stones of the treasury
had disappeared (Péan, 2004). A commission of inquiry
noted that a few French had entrusted their spoils to the
care of the consuls of England, Denmark and PiedmontSardinia, protected by diplomatic immunity (Flandin,
1835, p. 27). Did Bellecôte and the consul Peloso conceive
an ingenious stratagem to sell three diamonds that, in
reality, had been extracted from the Kasbah treasury? It is
possible, but not proven. Bellecôte did not participate to
the capture of Algiers in 1830, since he landed with the ‘‘4e
Régiment de ligne’’ 2 years later. Moreover, the diamond
still preserved at MNHN is less than one carat in weight,
uncut and it is obviously not a jewel, so the hoax is not
evident.
In the 1970s, Miocene lamproites were discovered in
the Constantine province (Kaminsky et al., 1993; Raoult
and Velde, 1971; Vila et al., 1974), reviving the interest for
the Constantine diamonds meanwhile forgotten. Although
new diamonds have not been found since 1833, this
discovery provides a possible primary source for the
Constantine diamonds.
2.2. Mineralogical observations
The three diamonds reportedly found at Constantine
were purchased in 1834 for the ‘‘École des mines’’, De Drée
and MNHN mineralogical collections. There is apparently
no mention of a diamond from Constantine at the ‘‘École
des mines’’; it could be one of the 23 diamonds of
‘‘unknown origin’’ that exist in the collection. De Drée’s
collection was sold to the MNHN in 1844 (‘‘Archives
nationales’’ [AN]: AJ/15/545). Only one diamond from
Constantine is still preserved at the MNHN (Fig. 2).
Labelled ‘‘MIN000-5608’’, it is recorded in the collection
catalogue as found in the ‘‘Constantine Basin’’ and sold in
1834 by Bellecôte for 100 Francs. Alfred Lacroix (1893–
1913, vol. 2, p. 354) described it as a ‘‘greenish octahedron,
with curved faces, weighting 91 milligrams’’, which does
not match the weight of ‘‘11/4 karat’’ (i.e., ca 250 mg)
mentioned for the same diamond by Héricart de Thury
(1840) (Table 1).
Under the optical microscope, the crystal appears as a
greenish octahedron ca 4.8 mm in size. The crystal weighs
91 mg, so it is evidently the one observed by Lacroix
(1893–1913). Raman spectrometry yielded a single band at
1333.5 cm 1, typical of diamond (ideally, 1332 cm 1).
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Fig. 2. (Colour online.) The diamond from Constantine preserved at the ‘‘Muséum national d’histoire naturelle’’ in Paris. Macroscopic view (below) and
secondary electron image (above); note the striations, the rounded edges and the left-bottom broken apex.
Observation under the scanning electron microscope
(SEM), without coating, reveals strongly rounded octahedron edges and apexes, and {111} faces with <110>
striations parallel to the edges (Figs. 2 and 3a). The
diagonals joining two opposite apices of the octahedron
(i.e., the 3 A4 axes), ideally equal, are 4.87, 4.65 and
4.77 mm long. Assuming a density of 3.517 for diamond,
the mass of 91 mg corresponds to a volume of 25.9 mm3.
Thus, the crystal appears to be a strongly rounded
octahedron, since its average diagonal length (4.76 mm)
is intermediate between that of an ideal octahedron
(5.37 mm) and the diameter of a sphere (3.67 mm) of the
same weight and volume.
The cathodoluminescence (CL) spectra obtained on
the SEM show a peak at ca 520 nm, corresponding to a
green colour. CL was also observed under an optical
microscope equipped with a vacuum chamber; it
revealed
numerous
30 mm-sized
circular
halos
(Fig. 3b), where the CL signal is strongly attenuated.
These halos, visible as dark-green spots under normal
light (Fig. 3a), are better visible in the SEM with the
Variable Pressure Secondary Electron (VPSE) detector;
they form circular dark roundels on the surface of the
crystal, on the faces as well as on the rounded edges
(Fig. 3c). The centres of the roundels are generally
arranged along superficial striations or cracks. Since the
VPSE signal shows how the surface dissipates charge,
these halos correspond to an electrically conductive
material, probably sp2-bonded carbon, either graphite or
amorphous C, present at the surface and contrasting
with the resistant sp3-bonded carbon of the surrounding
diamond. Such green halos are commonly interpreted as
being due to alpha radiation emanating from radioactive
minerals located in contact, or in close proximity, to the
diamond surface (e.g., Nasdala et al., 2013; see Fig. 2d
therein and our Fig. 3c).
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G. Godard et al. / C. R. Geoscience 346 (2014) 179–189
183
Fig. 3. (Colour online.) Radiohalos at the surface of the Constantine diamond: a: normal light under an optical microscope; b: cathodoluminescence under a
microscope equipped with a vacuum chamber and a cold cathode; c: variable pressure secondary electron image (20 kV) at the scanning electron
microscope.
No inclusions are visible under the optical microscope.
However, superficial very thin fractures are filled with a
TiO2-rich substance (Fig. 4a) and a few mm-sized crystals
have been observed under the SEM in superficial microcavities that display the negative crystal shapes of
diamond (Fig. 4b). These microcrystals did not yield
exploitable Raman spectra, and so could not be identified
with certainty, but their X-ray spectra obtained by SEM
using energy-dispersion spectrometry allowed qualitative
estimates of their chemical composition. Most of them
have the composition of muscovite, silica (probably
quartz) or biotite, whereas garnet, chromite and olivine
have not been observed.
2.3. Insight into the origin
The study of the MNHN diamond yields constraints on
its origin. The crystal, strongly rounded, has been
transported and reworked in sediments. A pebble of
quartz of the same weight and submitted to the same
hydrodynamics would have an average diameter of
4.1 mm, so the host sediment should have been a coarse
sand (or sandstone) or a microconglomerate. The microcrystals trapped in superficial irregularities mostly consist
of muscovite and silica, which do not normally exist in
kimberlite or lamproites and thus probably belonged to the
host sediment. The radius of the observed radiohalos
Fig. 4. Irregularities and fractures at the surface of the Constantine diamond. Observations at the scanning electron microscope in backscattered electrons:
a: superficial cracks filled with a TiO2-rich substance; b: microcrystals identified by energy-dispersion spectrometry (Mu: muscovite; Bi: biotite?; silica:
quartz?) in a microcavity that displays the negative shapes of diamond.
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(13.5–15.6 mm: Fig. 3c) matches those due to alpha decay
of 238U (from 12.3 to 16.0 mm, depending on the irradiated
material) and the other radionuclides of the same decay
chain, 226Ra, 230Th and 234U, which generate slightly larger
halos (Gentry, 1974). Since these radionuclides have long
half-lives (4.47 Ga for 238U) and because the halos also
formed on the rounded edges of the crystal, thus after its
transport and sedimentation, the diamond and its host
sediment should necessarily be ‘‘old’’.
Keeping in mind these requisites, three main hypotheses can be envisaged for the origin of the Constantine
diamonds:
the primary source could be Miocene ultrapotassic
lamproitic rocks that have been recognized in two places
within the Constantine region, at Koudiat Anzazza and
Kef Hahouner (Raoult and Velde, 1971; Vila et al., 1974)
and belong to a belt of lamproites that extends from
southeastern Spain to Tunisia (Kaminsky et al., 1993).
However, there are several objections to this hypothesis.
First of all, the radiohalos most probably exclude an age
as recent as Miocene. Moreover, Kaminsky et al. (1993)
concluded, on the basis of petrologic and geochemical
studies, that the Algerian Miocene lamproites are of too
shallow an origin to contain diamond. Finally, the two
Algerian occurrences do not belong to the Ghoumel basin
and hence cannot be the direct source of the diamonds –
at least, if these were really found in the Ghoumel River
near Constantine. To sustain this hypothesis, it would be
necessary to demonstrate that other lamproites occur in
the Ghoumel basin or that Miocene sediments might
have acted as an intermediate placer source;
the MNHN diamond could come from the Saharan
deposits situated 1500 km to the southwest (Fig. 1a).
This is supported by:
the halos that suggest an ancient age similar to that of
the Sahara diamonds, some of which also display darkgreen and brown radiohalos, present on the rounded
surfaces as well (Kaminsky et al., 1990, 1992b; see
Section 3),
its octahedral habit like 38% of the Bled-el-Mass
diamonds (see Section 3.1),
its rounded shape suggesting a long transport, also
inferred for many Sahara diamonds (Kaminsky et al.,
1990, 1992b; see Section 3.1),
its rarity, which can be explained by a long distance
from the primary source. A direct connection between
the Saharan deposits and Constantine during the
Quaternary is excluded, because the two regions are
separated by the sandy ‘‘Grand Erg occidental’’ that
impedes river flows. Sediments like microconglomerates and coarse sandstones that may have acted as
intermediate placers are not common upstream of
Constantine. The abundant marine Mesozoic sediments, mostly fine-grained limestones and marls (e.g.,
Joleaud, 1912), are hardly favourable. On the other
hand, the Numidian Flysch, dated as Oligocene to Early
Miocene, has quite a large extension upstream of
Constantine. Thomas et al. (2010) have recently
demonstrated, on the basis of detrital zircon ages and
palaeocurrent trends, that the Numidian sandstones are
derived from the Saharan ‘craton’ and/or its Early
Cretaceous cover; so that they could have served as a
secondary source, intermediate between the Saharan
diamondiferous formations and the Ghoumel fluvial
sediments;
finally, we cannot rule out the possibility of a hoax (see
Section 2.1), and hence of an origin far removed from the
Constantine region. It seems strange that the only 3
diamonds ever found near Constantine have been
discovered by a single person; as for the diamond sold
at Livorno a few years before 1721 (Magalotti, 1721,
1741), the merchant was from Constantine but not
necessarily the diamond. Moreover, the diamonds were
reportedly found in auriferous sediments, which do not
seem to be present in the Ghoumel River at Constantine;
some confusion may have arisen with two other rivers of
the Constantine province named Oued-Deheb (
;
i.e., ‘‘river of the gold’’) and known to be auriferous (e.g.,
Renou, 1848). It should be noted that this pessimistic
hypothesis is not incompatible with a Saharan origin,
since the only rough diamonds available in Algeria in
1833 were most probably from the Sahara (see below).
3. The Sahara diamonds
3.1. History of the finds
In 1849, the French adventurer Louis Du Couret [1812–
1867?], also called Hadji Abd-El-Hamid Bey—he claimed to
have converted to Islam—, initiated an expedition across
Africa, from Tunis to Cap town (sic), for which he received
instructions from the ‘‘Académie des sciences’’ (Élie de
Beaumont, 1849). The mission actually ended in January
1852 at Touggourt, to the North of the Algerian Sahara,
after an order of the French ‘‘Ministre de l’Instruction
publique’’ (Anonymous, 1851; Du Couret, 1853). Du Couret
brought back from Touggourt countless samples, maps and
manuscripts that are still preserved (see Note 1 in
Appendix A; Mantran, 1955). Soon afterwards, in 1854,
Alexandre Dumas edited a fanciful version of Du Couret’s
earlier journeys across equatorial Africa, in search of the
so-called tailed men of the Niam-Niam tribe (Du Couret,
1854). This hoax discredited Du Couret, so the French
‘‘Académie des sciences’’ did not publish the results of his
last mission to Touggourt and the MNHN accepted his
samples with much reluctance (AN: AJ/15/545). Du Couret
got a bad reputation of amateurishness if not of
charlatanism (Emerit, 1956; Hill, 1955) and, after various
cases against the French government (AN: 243AP/1) and
Alexandre Dumas (BNF: Ms NAF 18918), both accused of
not having complied with their commitments, his life
ended miserably (AN: F/18/273; Hill, 1955).
Du Couret might have been an amateur, but he brought
back from the Algerian Sahara various samples, unedited
maps and original manuscripts. While he was at Touggourt, he collected information on the geology of Sahara
from erudite persons of this region. In particular, Cid-ElHadj-Abd-El-Kader Ben-Abou-Bekr-Et-Touaty (thereafter
named Et-Touaty), born near Aoulef (Fig. 1b), wrote for him
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G. Godard et al. / C. R. Geoscience 346 (2014) 179–189
185
in Arabic a manuscript that describes the precious stones
of the Sahara, among which are ‘‘emeralds’’ and ‘‘diamonds’’ (see Note 2 in Appendix A; Bargès, 1853). EtTouaty wrote the following about diamond:
‘‘As for the diamond, we have found it in our country
[i.e., in the Aoulef region, near Akabli?], in the middle of
black stones. Since we had no tools to break it, we left it
in place. It resembled the grains of pomegranate, in the
middle of this darkish mass, reflecting a shiny colour,
like Pharaoh’s glass, grading from white to yellow. As
for the place, we have found the stone between Ouallen
and Akabli’’.
Writing in colloquial Arabic, Et-Touaty uses the Berber
name yamanta for diamond (
) instead of the Arabic
word mās (
), but there is no ambiguity, as confirmed by
Bargès’ translation in French, since yamanta or yamant is
still used in the Algerian dialect. Bargès’ translation, which
differs slightly from the manuscript (see Note 2 in
Appendix A), gives further details: the diamond, ‘‘excessively heavy’’, displays shiny colours, and the diamondiferous black stones are so hard that it is impossible to
break them with an iron tool, as they even break iron.
Akabli (26.7128N; 1.3708E) and Ouallen (24.6078N;
1.2878E) are two localities lying ca 250 km apart along the
ancient trans-Saharan caravan route from Aı̈n-Salah (NE)
towards Timbuktu (S). Ancient maps and travel records
(e.g., Gautier, 1907, 1908; IGN, 1930; Sabatier, 1891)
indicate that the route passed between Akabli and Ouallen
ca 50 km east of the Bled-el-Mass area (dashed line in
Fig. 1b), where diamonds have actually been discovered in
the 1970s. For the sake of convenience, we will call
hereafter the ‘‘Reggane region’’ the diamondiferous area
that extends around Bled-el-Mass, between Akabli to the
east, the Tidikelt Plateau to the north and the modern town
of Reggane to the west (Figs. 1b and 5).
Et-Touaty also provided Du Couret with one ‘‘emerald’’
and two ‘‘diamonds’’ (AS: 14 March 1853; BI: Ms 3817/V/2;
see Note 1 in Appendix A). Bargès’ version suggests that
these specimens have been found on the Tidikelt Plateau,
to the NE of Akabli (Fig. 1b), whereas the diamondiferous
black stones would have been found to the south: ‘‘As for
the places where we found the stones that we have
brought, [. . .] you should know that they are between Aı̈nGhar, Tit and Aoulef’’ (Fig. 1b; see Note 2 in Appendix A).
Du Couret was sceptical about these diamonds, since he
noted: ‘‘two diamond stones?? [question marks by Du
Couret]; these two transparent stones that [Et-Touaty]
gave to me could be diamond considering their density and
transparency’’ (AS: 14 March 1853). The two crystals were
catalogued at the MNHN as ‘‘small pebbles of hyaline
quartz’’ of an origin far removed from the Tidikelt region
cited by Et-Touaty and Du Couret (MNHN, catalogue Carré
500, no 28: ‘‘may be [. . .] between Touggourt and Biskra’’).
It is impossible now to settle the question, since the socalled diamonds are unfortunately missing among what
remains of Du Couret’s samples (19 out of 66) after
160 years in the ‘‘Galerie de minéralogie’’ at the MNHN. It
could be concluded that Et-Touaty’s diamonds are doubtful
and that Du Couret may have been fooled, but, as we will
see, the story is not so simple.
Fig. 5. (Colour online.) Geological map of the Bled-el-Mass area in the
Reggane region. Note the Devonian sediments with interbedded oolitic
ironstones, the dolerite dykes of the Central Atlantic Magmatic Province
(CAMP) and, to the northwest around Reggane Plateau (Tidikelt), the Early
Cretaceous that rests unconformably on the other formations.
As for the ‘‘emerald’’ (
; zumurrud) mentioned
by Et-Touaty, the sample that he gave to Du Couret has
been catalogued at the MNHN as ‘‘fragment of green
jasper’’ (MNHN: catalogue Carré 500, no 29), but again
this so-called emerald is missing from Du Couret’s
collection at the MNHN. The question of the ‘‘emerald’’
in the Reggane, Touat and Tidikelt regions has been
reviewed carefully by Flamand (1897), who considered it
plausible that it could be true emerald. On the other
hand, while criticizing Et-Touaty’s manuscript, he denied
the existence of diamond in the same region – wrongly,
as we will see. Actually, it is admitted today that the
mythic Sahara emeralds, known to the ancient Romans
and otherwise called the emerald of the Garamantes
after an antique Berber tribe, are not truly emerald in the
modern sense but could be any kind of emerald-green
semi-precious stone, among which is amazonite (e.g.,
Monod, 1974).
The first geological survey of the Reggane region was
performed around 1900 by Laperrine, Flamand (1897), and
mostly by Émile Gautier (1907, 1908) who carried out the
geological study and mapping of an area called ‘‘Bled-elMass’’ (see supplementary material, SM1). Gautier apparently did not notice that ‘‘Bled-el-Mass’’ means ‘‘Country of
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G. Godard et al. / C. R. Geoscience 346 (2014) 179–189
the diamond’’ in Arabic (
; Bilād al-mās in modern
transcription). The topographic maps published since 1930
locate Bled-el-Mass between Reggane and Akabli, at ca
26.618N–0.628E (e.g., IGN, 1930).
The first modern discovery of diamond in the Algerian
Sahara was made in 1953 by Ranou, at In Zize, in the
northern part of the In Ouzzal terrane (western Hoggar:
Fig. 1a). The diamond recovered was a rounded crystal of
0.2 carat weight (Kahoui et al., 2008; Kaminsky et al.,
1992b; Meindre, 1959; Thébault, 1959; Touahri et al.,
1996). In 1958, a carbonado of 0.1 carat was found at
Tibeghim near Silet in the central Hoggar, as well as seven
fragments of spinel (Meindre, 1959; Touahri et al., 1996).
After these first discoveries, an intensive exploration for
diamonds was undertaken in the Hoggar in the 1960s–
1970s. As a result of these campaigns, one small (0.36 mm)
dodecahedral diamond was found in 1969 by V. Izarov in
the Tiririne area, in the eastern Hoggar (Kaminsky et al.,
1992b).
In light of these poor results, prospecting for diamonds
in the Algerian Sahara moved to the north, towards the
Reggane and Touat regions where two diamonds had been
found in 1975–1976 (Touahri et al., 1996). Between 1978
and 2001, a high concentration of diamonds was discovered in the Reggane region, in the Bled-el-Mass Valley
(Fig. 5): 1485 at Djebel Aberraz, 16 to the south of Aı̈n
Chebbi and 26 at Bled-el-Mass (Bouarroudj, 2005; Kahoui
et al., 2008, 2012). The diamonds occur in alluvial deposits
of Quaternary age that are up to 12–15 m thick. The
crystals have rounded shapes with octahedral (38%),
dodecahedral (25%) and combined (22%) habits; they
range in weight from 1.5 mg to 45 mg (Bouarroudj, 2005),
and contain micro-inclusions of sulphides, chromite,
chrome diopside and garnet (Kaminsky et al., 1990,
1992b).
In 1989, a diamond was found by M. Wilczynski near El
Kseibat (Adrar, Touat region), ca 160 km to the NNW of
Reggane (Fig. 1). Since then, more than 19 small detrital
diamonds have been recovered in this area (Belghaı̈t, 2003;
Kahoui et al., 2012), which makes the El Kseibat placer
deposit the second most important concentration of
diamonds in the Algerian Sahara.
More recently, new diamond occurrences have been
found in the Hoggar (Fig. 1a):
a diamond was found in 2001 in the Tiririne-Hanane area
(ORGM, 2003);
in 2002, a diamond 1 1 0.35 mm in size was
discovered near Silet (ORGM, 2003);
three diamonds were found in 2002 in the southern part
of the In Ouzzal (western Hoggar; Zerrouki, 2007).
In addition, diamond indicator minerals such as
pyrope-rich garnet, chrome spinel and picroilmenite were
discovered in an area that stretches on 700 km around
Reggane, from the Tanezrouft in the southwest to El
Kseibat (Adrar) in the northwest (Fig. 1b; Bouarroudj,
2005; Kahoui et al., 2012). Pyrope, kimberlitic ilmenite,
chrome spinel and chrome diopside were also found in the
In Ouzzal, Silet and Tiririne areas, in the Hoggar massif
(ORGM, 2003; Zerrouki, 2007).
3.2. Insight into the origin
Bled-el-Mass, the ‘‘country of the diamond’’ where
diamond has been found in placer deposits in the 1970s, is
a few tens of kilometres to the west of Akabli (Figs. 1b and
4). This fact gives credibility to Et-Touaty, who located his
diamondiferous ‘‘black stone harder than iron’’ between
Akabli and Ouallen, although the two so-called diamonds
that he gave to Du Couret are doubtful and might come
from another place (see above). Et-Touaty’s manuscript
insinuates that the ancient Arabs knew the source rock,
looked for in vain by modern geologists over the last
decades.
What could this rock be? At Bled-el-Mass there are
wide dykes and sills of a dark fine-grained volcanic rock
(Fig. 5) that could match Et-Touaty’s description, and such
an origin for the diamond has already been proposed by
Thébault (1959). However, these dykes are apparently all
tholeiitic dolerites of the Central Atlantic Magmatic
Province rather than ultrapotassic lamproitic rocks (Chabou et al., 2007, 2010), so they are not favourable to the
presence of diamond.
Other rocks might correspond to Et-Touaty’s description. One possibility is the oolitic ironstones interbedded
within Devonian sediments that crop out from Bled-elMass (Fig. 5) to the region that extends between Akabli and
Ouallen (Fig. 1 in Guerrak, 1987). These rocks are black,
very hard and show oolitic to micro-conglomeratic facies
(Guerrak, 1987) that resemble ‘‘the grains of pomegranate’’. This formation, which could have acted as placer,
deserves some consideration since it surprisingly matches
all the features reported by Et-Touaty.
Modern authors have preferred a kimberlitic origin for
the primary source of the diamonds in the Reggane region,
without excluding lamproites. They have pointed out that
a local occurrence of the primary source in the Bled-elMass area is unlikely, as the latter is located outside the
craton, in the Pan-African mobile belt, which is not
favourable for the emplacement of diamondiferous kimberlites. Lamproite occurrences in the Reggane region
cannot be excluded, however, as several diamondiferous
lamproite bodies have been discovered within similar
mobile belts (e.g., Ellendale lamproitic deposits in western
Australia: White et al., 1995). Kahoui et al. (2008)
advocated a primary kimberlitic source further west in
the Eglab shield of the West African Craton, where Allek
and Hamoudi (2008) recognized three target areas
favourable for kimberlite emplacement on the basis of
geological and geophysical criteria. On the other hand,
Semiani and Lardjane (2010) invoked an eastern provenance on geomorphological grounds. Although much older
ages have been envisaged (Kechid, 2007), these hypothetical kimberlites could be Jurassic, like the 21 kimberlite
bodies recently found in northern Mauritania (Rombouts,
2003); this would be compatible with the presence of
indicator minerals reworked in the Early Cretaceous cover.
Northwards of the Reggane region, coarse sediments of
the Early Cretaceous, known in northern Africa as
‘‘Continental intercalaire’’ (e.g., Lefranc and Guiraud,
1990), rest unconformably on the Saharan basement and
form the Tidikelt Plateau (Fig. 5). Several authors have
Author's personal copy
G. Godard et al. / C. R. Geoscience 346 (2014) 179–189
proposed this formation as an intermediate source, since
grains of pyrope with kimberlitic features have been
found in it (Kahoui et al., 2012; Kaminsky et al., 1992a,b;
Sobolev et al., 1992). Considering that the Bled-el-Mass
diamonds are rounded and show typical features of a
marine-shore environment, Kaminsky et al. (1992b)
suggested that they could originate from the reworking
of such Cretaceous sediments cropping out on the
Tidikelt Plateau at a few kilometres upstream of the
Djebel Aberraz deposit in the Bled-el-Mass area (Fig. 5); a
similar origin has been suggested for the El Kseibat
occurrence (Kahoui et al., 2012). Besides the two doubtful
diamonds that Et-Touaty gave to Du Couret (Bargès,
1853), only one small diamond chip of 0.15 mm has been
found on the Tidikelt Plateau (Kaminsky et al., 1992b).
Much to the southeast, diamonds are mined from the
Continental Intercalaire sandstones of the Central African
Republic (e.g., Lefranc and Guiraud, 1990).
The radiohalos described by Kaminsky et al. (1990, p. 79;
1992b) at Bled-el-Mass are of a great importance. They link
the Constantine diamond to those of the Sahara, and above
all they can provide a key to the recognition of the source
rock, which must necessarily be ‘‘old’’ and contain radioactive microcrystals. These spots are observed on the eroded
parts of the diamond crystals from Bled-el-Mass (Kaminsky
et al., 1990) and from Constantine (Fig. 3), which implies
that they formed in a sedimentary rock. In both occurrences,
the spots display a regular concentric structure (Kaminsky
et al., 1990; Fig. 3c); on the MNHN diamond surface, the halo
centres, from which emanated the alpha radiation, are mmsized and seem arranged along superficial striations or
cracks (Fig. 3c). This is hardly compatible with detrital zircon
or monazite grains but rather suggests uraniferous microcrystals formed in the sediment at the surface of the
diamond crystals.
4. Conclusion
Although the early finds of diamonds at Constantine
(1833) and in the Sahara between Akabli and Ouallen by
Et-Touaty (ca 1851) are debatable, it can be concluded that
the ancient Arabs and/or Berbers knew some of the
Algerian diamond occurrences, which were probably the
first ever found in Africa in historical times, before the
discoveries in South Africa in 1867 (see Boutan, 1886). This
is undoubtedly testified to by the Arabic name Bled-elMass (i.e., ‘‘Country of the diamond’’), given in ancient time
to a region situated to the west of Akabli in the Reggane
region and where diamonds have actually been found.
However, like the emerald of the Garamantes, the diamond
issue in ancient Algeria is difficult to sort out, since it
consists of an inextricable mixture of false and true
information, of myth and reality, of imaginary and real
diamonds.
The scarce information and samples that are related to
these early finds can contribute to unravelling the origin of
the diamonds. The Constantine diamonds might have a
Saharan origin through an intermediate palaeoplacer, but
this occurrence remains uncertain. As for the diamonds of
the Reggane region, modern investigations have favoured
Jurassic kimberlites that are yet be found in the West
187
African Craton, as a primary source, and the Early
Cretaceous cover as a secondary source. Et-Touaty’s
manuscript insinuates that the ancient Arabs or Berbers
knew the source rock, which has been sought in vain for
decades by modern geologists, and calls our attention to
other possible sources. The diamondiferous ‘‘black stone
harder than iron’’ briefly described by Et-Touaty can hardly
refer to lamproites, unknown in this region, but it may
depict Devonian oolitic ironstones, which deserve some
attention, although not considered as a potential diamond
placer till now. Finally, the regular concentric radiohalos
observed at the surface of the Bled-el-Mass and Constantine diamonds should be considered carefully, as they
could lead to the recognition of the intermediate sedimentary source.
There remains some chance to get more information on
the diamond occurrences of the Reggane region, by
assessing the ancient manuscripts that are preserved in
the Touat khizanat. The Touat is an archipelago of oases
that stretches on ca 150 km to the north of Reggane
(Fig. 1b). It has been an important centre of civilization and
still preserves numerous Arabic manuscripts (Bouterfa,
2005). Although most of these are devoted to religious or
historical matters, a few of them deal with science. Their
inventory, which has been initiated a few years ago and is
still in progress (Bouterfa, 2005), might provide further
information on how and where the diamonds were found
by the Berbers and Arabs in the Reggane region.
Acknowledgments
This article is dedicated to the memory of Michel
Durand-Delga [1923–2012], geologist of Algeria and
historian of geology. Gabriel Carlier, Cristiano Ferraris
and Caroline Noyes are warmly thanked for having
facilitated our investigation of the Constantine diamond
and Du Couret’s samples in the MNHN collections. Didier
Nectoux did the same at the École des mines. Giuliana Frati
has brought Pliny’s and Saint Augustine’s texts to our
attention. Abbas Hamzaoui of the Sétif University (Algeria)
guided us on the lamproite occurrences of the Constantine
province. We sincerely thank Profs William Griffin and
Jacques Touret for their constructive and positive review of
the manuscript and M. Chaussidon for the editorial
handling.
Appendix A
Note 1: the original manuscripts of Du Couret’s mission
are preserved at:
Archives nationales de France (AN): 243AP/1 (correspondence); F/17/2957/B (reports, maps, correspondence); AJ/15/545 (samples); F/18/273 (demand for a
pension);
Bibliothèque de l’Institut (BI): ms 4483 (letter) and 3817/
V/2 (geological samples);
Archives de l’Académie des sciences (AS): ‘‘pochette de la
séance du 14 mars 1853’’ (geological samples, scientific
reports);
Author's personal copy
188
G. Godard et al. / C. R. Geoscience 346 (2014) 179–189
Muséum national d’histoire naturelle (MNHN): Carré
467, 500 and 634 (catalogues of geological samples);
Centre des archives d’Outre-mer, Aix-en-Provence: FR
ANOM 50COL1 (correspondence, notes).
Note 2: Et-Touaty’s manuscript was written on 14
September 1851, in old Maghribi Arabic script, revised and
completed under Et-Touaty’s control by Mohammed Abd-ElDjellil, one of Du Couret’s companions, and sent from
Touggourt on 6 January 1852. Two copies of this manuscript
are preserved at the ‘‘Archives nationales de France’’ (AN: F/
17/2957/B, pièces 2 & 139); the second is available as
supplementary material of this article. Du Couret’s report
also comprises a French translation of the manuscript by
l’abbé Bargès (AN: F/17/2957/B, rapport, pp. 604–607),
published later on (Bargès, 1853). This translation differs
significantly from the manuscript, so that Bargès had
probably another Arabic version at his disposal.
Appendix B. Supplementary data
Supplementary data associated with this article can be
found, in the online version, at http://dx.doi.org/10.1016/
j.crte.2014.03.007.
References
Agricola, G., 1546. De Natura Fossilium. Froben & Episcopius, Basel (lib.
VI).
Allek, K., Hamoudi, M., 2008. Regional-scale aeromagnetic survey of the
Southwest of Algeria: a tool for area selection for diamond exploration. J. Afr. Earth Sci. 50, 67–78.
Anonymous, 1835a. Diamonds at Algiers. Am. J. Sci. Arts 28, 394.
Anonymous, 1835b. Diamonds in Africa. Rec. Gen. Sci. 1, 475.
Anonymous, 1835c. Die Diamanten Afrikas. Pharm. Ztg. Apoth.-Ver.
Noerd. Dtschl. 9, 9–11.
Anonymous, 1851. Nouvelles des missions. Archives des missions scientifiques et littéraires : choix de rapports et instructions publié sous les
auspices du ministère de l’Instruction Publique et des Cultes. 2, 407–
408.
Bargès, A., 1853. Le Sahara et le Soudan ; documents historiques et
géographiques recueillis par le Cid-el-Hadj-Abd’-El-Kader-BenAbou-Bekr-Et-Touaty, avec un alphabet touareg inédit. Rev. Orient
Alger. Colonies 13, 73–91.
Belghaı̈t, T., 2003. Traitement des échantillons volumineux des dépôts
plio-villafranchiens diamantifères de la Hamada Chemmar (El Kseibat-Ougarta). In: 2e séminaire national de stratigraphie ; recueil des
résumés, Beni Abbes, Algérie, p. 46.
Bouarroudj, M.T., 2005. L’exploration du diamant en Algérie : principaux
résultats et perspectives. In: Colloque sur l’état de la Recherche et du
Développement du secteur minier dans le monde arabe, Rabat, 13–15
déc. 2005.
Boutan, E., 1886. Le diamant. Dunot, Paris (323 p.).
Bouterfa, S., 2005. Les manuscrits du Touat : le Sud algérien. Éd. Barzakh,
Alger, [102 p.]
Chabou, M.C., Bertrand, H., Sebai, A., 2010. Geochemistry of the Central
Atlantic Magmatic Province (CAMP) in southwestern Algeria. J. Afr.
Earth Sci. 58, 211–213.
Chabou, M.C., Sebai, A., Feraud, G., Bertrand, H., 2007. Datation 40Ar/39Ar
de la province magmatique de l’Atlantique central dans le Sud-Ouest
algérien. C. R. Geoscience 339, 970–978.
Coquand, H., 1854. Description géologique de la province de Constantine.
Mem. Soc. geol. France 2es (1) (155 p. + 5 pl).
d’Avezac de Castera-Macaya, P., 1835–1836. Note. In: Ritter, K. (Ed.),
Géographie générale comparée [. . .]. Traduit de l’allemand par
E. Buret et E. Desor. Paulin, Paris, pp. 389–417.
Du Couret, L., 1853. Mémoire à Sa Majesté Napoléon III, empereur des
Français, par le hadji Abd-el-Hamid Bey [. . .] sur les résultats de la
mission officielle que ce voyageur vient de remplir en Afrique. Pommeret et Moreau, Paris (16 p.).
Du Couret, L., 1854. Voyage au pays des Niam-Niams ou hommes à queues
par Hadji Abd-el-Hamid Bey ; avec un portrait d’un Niam-Niam et une
notice biographique sur l’auteur par Alexandre Dumas. Martinon,
Paris (102 p.).
Dufrénoy, A., 1834. Sur les diamants des environs de Constantine. Bull.
Soc. geol. France 4, 164.
Dureau de La Malle, A., 1837. Province de Constantine, recueil de
renseignemens pour l’expédition et l’établissement des Français dans
cette partie de l’Afrique septentrionale. Gide, Paris (xvi-315 p.).
Élie de Beaumont, L., 1838. Rapport de la Commission chargée, sur
l’invitation de M. le ministre de la Guerre, de rédiger des instructions
pour une exploration scientifique de l’Algérie. Instructions pour la
géologie. C. R. Hebd. Seances Acad. Sci. France 7, 142–182.
Élie de Beaumont, L., 1849. Voyages scientifiques. Instructions démandées par M. le Ministre de l’instruction publique, et destinées à M. le
colonel Ducouret. Minéralogie et géologie. C. R. Hebd. Seances Acad.
Sci. France 29, 211–212.
Emerit, M., 1956. Un collaborateur d’Alexandre Dumas : Ducouret Abd alHamid. Cah. Tunis. 4, 243–249.
Flamand, G.B.M., 1897. Productions du Touat ; productions minérales.
Aperçu général sur la géologie du Bassin de l’Oued Saoura et des
régions limitrophes. In: Lacroix, N., de La Martinière, H.P. (Eds.),
Documents pour servir à l’étude du Nord-Ouest africain. Gouvernement général de l’Algérie, service des affaires indigènes, Alger (III,
241–307, 473–540).
Flandin, J.B., 1835. Prise de possession des trésors d’Alger : requête
présentée par M. Flandin, sous-intendant militaire. Jules Didot l’Aı̂né,
Paris (32 p.).
Fournel, H., 1849–1854. Richesse minérale de l’Algérie, 2 vol. Imprimerie
nationale, Paris (xvii-476, xi-240 p. + atlas [20 pl.]).
Gautier, E.-F., 1907. Études Sahariennes. Ann. Geogr. 16, 46–69.
Gautier, E.-F., 1908. I. Sahara algérien. In: Gautier, E.-F., Chudeau, R.
(Eds.), Missions au Sahara, 2 vol. A. Colin, Paris (+ pl. et cartes).
Gentry, R.V., 1974. Radiohalos in a radiochronological and cosmological
perspective. Science 184, 62–66.
Guerrak, S., 1987. Metallogenesis of cratonic oolitic ironstone deposits in
the Bled-el-Mass, Azzel Matti, Ahnet and Mouydir basins, Central
Sahara, Algeria. Geol. Rundsch. 76, 903–922.
Guyon, 1834. Sur l’ancienne Cirta, aujourd’hui Constantine. Monit. Alger.
105, (also: no 94, 9 nov. 1833).
Heeren, A.H.L., 1799. Handbuch der Geschichte der Staaten des Alterthums, mit besonderer Rücksicht auf ihre Verfassungen, ihren Handel
und ihre Colonien, zum Gebrauch öffentlichen Vorlesungen.
J.G. Rosenbuch’s Wittwe, Göttingen (xii-576 p.).
Héricart de Thury, L.E., 1840. Découverte de diamants en Algérie. Rev.
Encyclopedique Connaissances Hum. Part. Sci. 10, 571.
Hill, R., 1955. Louis du Couret. Fr. Stud. 9, 143–153.
IGN, 1930. Carte du Sahara au 200 000e ; feuille Reggane, NG-31-XIII ; 1re
éd. [+2e éd., 1967]. Institut Géographique National, Paris.
Joleaud, L., 1912. Étude géologique de la chaı̂ne numidique et des monts de
Constantine, Algérie. Montane Sicardi et Valentin, Montpellier (439 p.).
Kahoui, M., Kaminsky, F., Griffin, W.L., Belousova, E., Mahdjoub, Y.,
Chabane, M., 2012. Detrital pyrope garnets from the El Kseibat area,
Algeria; a glimpse into the lithospheric mantle beneath the northeastern edge of the West African Craton. J. Afr. Earth Sci. 63, 1–11.
Kahoui, M., Mahdjoub, Y., Kaminsky, F., 2008. Possible primary sources of
diamond in the North-African diamondiferous province. In: Ennih, N.,
Liegeois, J.P. (Eds.), The boundaries of the West African Craton.
Geological Society Special Publications 297, London, pp. 77–109.
Kaminsky, F., Kolesnikov, S.K., Petelina, N.A., Khamani, M., Khenni, A.,
Khufani, M., Verzhak, V.V., Azzi, A., 1992a. Minerals associated with
diamond in the Algerian Sahara [in Russian]. Mineralogicheskiy Zh.
[Kiev] 14, 15–25.
Kaminsky, F., Konyukhov, Y.I., Verzhak, V.V., Khamani, M., Khenni, A.,
1990. Diamonds from the Algerian Sahara [in Russian]. Mineralogicheskiy Zh. [Kiev] 12, 76–80.
Kaminsky, F., Romanko, Y., Kolesnikov, S., Salkhi, M., 1993. Lamproites of
northern Algeria. Int. Geol. Rev. 35, 235–252 (translated from: Izvestiya
Akademii Nauk SSSR. Seriya Geologicheskaya, 1992, issue 10, pp. 56–71).
Kaminsky, F., Verzhak, V.V., Dauev, Y.M., Buima, T., Boukhalfa, L., Kaui, M.,
Salhi, A., Slugi, M., 1992b. The North-African diamondiferous province. Russ. Geol. Geophys. 33, 91–95.
Kechid, S., 2007. Hypothèse d’une accrétion océanique éburnéenne et ses
implications sur l’origine des kimberlites et éclogites sahariennes
(Algérie). Bull. Serv. Geol. Nat. 18, 263–275.
Lacroix, A., 1893–1913. Minéralogie de la France et de ses colonies :
description physique et chimique des minéraux, étude des conditions
géologiques de leurs gisements, 5 vol. Baudry, Paris.
Author's personal copy
G. Godard et al. / C. R. Geoscience 346 (2014) 179–189
Lefranc, J.P., Guiraud, R., 1990. The Continental Intercalaire of northwestern Sahara and its equivalents in the neighbouring regions. J. Afr.
Earth Sci. 10, 27–77.
Magalotti, L., 1721. Sopra un intaglio, in un diamante. A Monsignor Leone
Strozzi. Lettera XVII. Lettere scientifiche ed erudite del conte Lorenzo
Magalotti. per i Tartini e Franchi, Firenze (xxiv-303 p.).
Magalotti, L., 1741. Lettere familiari del conte Lorenzo Magalotti.
G. Bettinelli, Firenze (xvi-271 p.).
Mantran, R., 1955. Une relation inédite d’un voyage en Tunisie au milieu
du 19e siècle. Cah. Tunis. 3, 474–480.
Meindre, M., 1959. Principales minéralisations du Hoggar (Sahara algérien). Chron. Mines Outre-Mer 271, 9–22 (+ carte).
Monod, T., 1974. Le mythe de l’émeraude des Garamantes. Antiquites Afr.
8, 51–66.
Nasdala, L., Grambole, D., Wildner, M., Gigler, A.M., Hainschwang, T.,
Zaitsev, A.M., Harris, J.W., Milledge, J., Schulze, D.J., Hofmeister, W.,
Balmer, W.A., 2013. Radio-colouration of diamond: a spectroscopic
study. Contrib. Mineral. Petrol. 165, 843–861.
ORGM, 2003. Silet. Découverte d’un grain de diamant. Bull. Prospect 20, 1.
Papier, A., 1873. Essai d’un catalogue minéralogique algérien. Bull. Acad.
Hippone 11, 5–211 (+ Tables).
Péan, P., 2004. Main basse sur Alger : enquête sur un pillage, juillet 1830.
Plon, Paris (271-[12] p.).
Raoult, J.-F., Velde, D., 1971. Découverte de trachytes potassiques à olivine
et d’andésites en coulées dans le Miocène continental au Sud du Kef
Hahouner (Nord du Constantinois, Algérie). C. R. Acad. Sci. Paris Ser. D
272, 1051–1054.
Renou, E., 1848. Description géologique de l’Algérie. Exploration scientifique de l’Algérie. Imprimerie nationale, Paris (iv-182 p. + 4 pl).
Rombouts, L., 2003. Distribution of diamonds and kimberlites on the
Reguibat craton, ;auritania. In: 8th International Kimberlite
Conference. Victoria, Canada, 22–27 June 2003, (abstract), p. 14.
189
Sabatier, C., 1891. Touat, Sahara et Soudan : étude géographique, politique, économique et militaire. Société d’éditions scientifiques, Paris
(336 p.).
Semiani, A., Lardjane, T., 2010. Quelle origine pour les diamants de
Reggane ? In: 1er Colloque international sur la géologie du Sahara
algérien : ressources minérales, hydrocarbures et eau, Ouargla, 5–7
déc. 2010, pp. 205–209.
Sobolev, N.V., Afanas’yev, V.P., Pokhilenko, N.P., Kaminsky, F.V., Tarasyuk,
O.N., Henni, A., 1992. Pyropes and diamonds from the Algerian Sahara,
Doklady. Earth Sci. Sect. 326, 151–157.
Thébault, J.Y., 1959. Problème de la recherche du diamant en pays
saharien et plus précisement au Hoggar. Bull. Sci. Econ. Bur. Rech.
Min. Alger. 6, 65–81.
Thomas, M.F.H., Bodin, S., Redfern, J., Irving, D.H.B., 2010. A constrained
African craton source for the Cenozoic Numidian Flysch: implications
for the palaeogeography of the western Mediterranean basin. Earth
Sci. Rev. 101, 1–23.
Touahri, B., Fabre, J., Piboule, M., Kaddour, M., 1996. Les diamants du Bled-elMass (Touat) : contexte géologique. Mem. Serv. Geol. Alger. 8, 159–172.
Vila, J.-M., Hernandez, J., Velde, D., 1974. Sur la présence d’un filon de
roche lamproı̈tique (trachyte potassique à olivine) recoupant le flysch
de type Guerrouch entre Azzaba (ex-Jemmapes) et Hammam-Meskoutine, dans l’Est du Constantinois (Algérie). C. R. Acad. Sci. Paris, Ser.
D 278, 2589–2592.
Ville, L., 1869. Notice sur les gı̂tes minéraux et les matériaux de construction de l’Algérie. Ann. Mines 16, (70 p.).
White, S.H., de Boorder, H., Smith, C.B., 1995. Structural controls of
kimberlite and lamproite emplacement. J. Geochem. Explor. 53,
245–264.
Zerrouki, A., 2007. Principaux résultats et perspectives de l’exploration du
diamant en Algérie. In: 6e séminaire de géologie pétrolière, Boumerdès, Algérie, 15–16 avril 2007.